The owner of the image are who have to decide the uses of their images. "All rights reserved" means that: the owner have rights for any use of images now and whatever someone invent in the future.

In an ideal world, each image of a dataset used in machine learning have to be identified with author and license. But I understand that is difficult to achieve because images are copied in the www and it is difficult locate the original source.

So, I have no doubt about the illegality of use images from web scrapping. Other thing is how easy is win/loss a lawsuit and to prove you used that data or not.

The style of graph is nice for informal report (copy of xkcd), but if the difference of the experiments at the end are 1º C, it is the worst style to use because you can't know if the difference at the end is because the data or the drawing style of lines.